Air impeller



Dec. 18, 19 M. c. MODERMENT AIR IMPELLER Filed March 2, 1950 w w M Z 40b. Z

ATTORNEY Patented Dec. 18, 1951 AIR IMPELLERJ Matthew G2.Mcl)erment,Elizabeth, N. 3;, assignor to. The Singer Manufacturing Company;Elizabeth,.N. J.,, a corporation of New Jersey 7 ApplicatiomMarclr-Z,1950,,SerialNo. 147,193:

2Claims.

This invention relates to propeller typefan bladessuitable for use in.freeair. fanssuch: as are employed in the household and in the office.More specifically, this invention relates to a novel construction of anair impeller comprising four individual blade elements, the inner endportions of which are secured together thereby to form a unitaryimpeller having a rigid hub portion.

A primary object of my invention is to provide an impeller of the abovenoted type which will be economical of manufacture and at the same timewill present a dynamically balanced structure which will produce aminimum of noise and vibration during its operation.

With the above and other objects in view, as

will hereinafter appear, the invention comprises the devices,combinations and arrangement of parts hereinafter set forth andillustrated in the accompanying drawings of a preferred embodiment ofthe invention, from which the several features of the invention and theadvantages attained thereby will be readily understood by those skilledin the art.

In the drawings,

Fig. 1 represents a front elevation view of my improved air impeller.

Fig. 2 represents a front elevation view of one of the four identicalblades which make up the air impeller proper.

Fig. 3 represents a sectional view taken substantially along the line 33of Fig. 2.

Fig. 4 represents, on an enlarged scale, a fragmentary sectional viewtaken substantially along the line 44 of Fig. 1.

In the embodiment illustrated, and referring to the numerals of thedrawings, my improved impeller comprises four identically shapedindividual wings, or blades, generally designated by the numerals 5, 5,l and 8, which blades are secured together at their inner end portionsthereby to form a central hub structure 9 which is carried upon a hollowhub sleeve It. The outer air-impelling surfaces of the blades may be ofany conventional shape.

Each of the blades 5, 5, l and 8, may be formed of any suitablematerial, but in a preferred form of the invention they are fabricatedof sheet metal. Since all of the blades are identical in shape, they mayeach be formed from a single die set when they are to be fabricated fromsheet metal.

Each of the present blades is provided at its inner end with a fiat andsubstantially rectangular terminal ear I I which is provided centrallyof its marginal edge portion with a semicircular notch 12.. Also,v eachblade is formed with a radiallydisposed ribv or nodule is extending froma: location adjacent the notchl2. to a location substantially midwaybetween the inner and outer end portions of the blade for the purpose ofstrengthening the same. The terminal ear I! of each blade is formedalong its marginal edge portion at each side of the notch l2 with acurved flange or nodule l4 shaped as one-half of a rib section which isdisposed at right angles to the radial blade rib I3.

In constructing the complete impeller structure, the terminal earportions I|Il are abutted in pairs and then the two pairs are stackedtogether in a manner such that the ear notches |2-l2 will define acentral hub aperture, and the abutting ear flanges I l-l4 of half ribswill form complete short ribs which will nest with the correspondingradial wing ribs. To complete the impeller unit, the stacked ears ll--l|are secured together by a plurality of rivets l5 which pass throughsuitable apertures 16, and the reduced shoulder portion ll of thecentrally apertured hub element I8 is inserted into the hub aperture andspun over, as at It), against one face of the impeller hub, therebylocking the impeller unit to the hub element. The hub element I0, beingprovided with a central aperture 19 and a threaded radial aperture 20,may be mounted upon the exposed portion of an impeller-actuating shaftand locked on such shaft by means of a set screw received within thethreaded aperture 20.

Those skilled in the art will readily appreciate that the nested ribstructure of the present impeller unit facilitates the accurate assemblyof the individual blades and at the same time strengthens the hubsection and locks the various blades against relative rotation.Furthermore, since all of the blades are identical in shape and aremounted together in a symmetrical fashion, there is automaticallyproduced an impeller unit which is dynamically balanced so that it haslittle or no tendency to produce vibration and noise during itsoperation.

Having thus set forth the nature of the invention, what I claim hereinis:

1. An air impeller comprising, four blades each having an outerair-impelling portion and an inner rectangular terminal ear portionbeing formed with a substantially straight marginal edge, a rib formedon and longitudinally of each blade and extending from a locationadjacent said straight marginal edge of said ear to a locationintermediate the inner and outer end portions of the blade, a curvedflange shaped as one-half of a rib section formed on the said marginaledge of each blade and disposed at right angles to said longitudinalrib, said blades being abutted in pairs at the said marginal edges oftheir terminal ears and having the two pairs of blades stacked togetherwith the abutting ear flanges forming a complete rib which nests with acorresponding longitudinal rib, and means securing said blades rigidlytogether in such stacked relation.

2. An air impeller comprising, four blades each having an outerair-impelling portion and an inner rectangular terminal ear portionbeing formed centrally of its marginal edge with a semicircular notch, arib formed on and longitudinally of each blade and extending from alocation adjacent the notch to a location intermediate the inner andouter end portions of the blade, a curved flange shaped as one-half of arib section formed on the said marginal edge of each blade at each sideof the notch and disposed at right angles to said longitudinal rib, saidblades being abutted in pairs at the said 4 marginal edges of theirterminal ears and having the two pairs of blades stacked together in amanner such that the ear notches define a central hub aperture and theabutting ear flanges form complete short ribs which nest with thecorresponding longitudinal ribs, and means securing such blades rigidlytogether in such stacked relation.

MATTHEW C. MCDERMENT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

